The present invention relates generally to gas generating systems and, more particularly, to gas generators used in vehicle occupant protection systems. It is contemplated that the present invention may also be useful in other gas generating contexts such as inflatable rafts for example.
Certain known gas generators utilize pyrotechnic gas generating compositions that when combusted produce inflating gases to actuate or inflate airbags, cushions, curtains, and other vehicle safety equipment such as seatbelt pretensioners.
With the advent of non-azide compositions, or azide-free compositions, there is a greater need for cooling the effluent gases of the gas generator given that non-azide compositions typically combust at relatively greater temperatures as compared to azide-based compositions. Accordingly, filters and/or heat sinks have been typically employed to manage both filtration of solids in the gaseous effluent, and, cooling of the effluent gases as the heat of the gases is exchanged with the cooler filter or heat sink. One drawback with the use of filters or heat sinks is the relative increase in mass or weight of the gas generator. Filters are typically formed from roll-formed woven metal, for example, and constitute a large percentage of the overall mass of the gas generator or inflator.
A reduction in the mass of the gas generator, and a reduction in the overall size of the inflator, without sacrificing the total gaseous output, would therefore be an improvement in the art given the packaging benefits, and given the reduction in manufacturing complexity and cost. The current challenge, therefore, is to optimize the filtration and cooling requirements thereby obviating or mitigating the need for the typical robust filter designs.